When the speakers were wired for the room, the installer placed 2 in-ceiling surround fronts (almost in the front corners of the room) - 2 in-ceiling surround left & rights at the sides of the sitting area, and 2 in-ceiling rears behind the sitting area.
He said that they were directional speakers and aimed the tweeters toward the sitting area.
The current center channel speaker acts (and sounds) like the strongest directional speaker in the setup. It's a pretty solid sound field especially in 7-Stereo channel. I agree now that it may have been better to install the 2 surround fronts in the wall instead of the ceiling.
There are a variety of Niles options for the front center. Do I have to get the exact same speakers, or can I mix and find a center from the Niles family?